1. Field of the Invention
The present invention relates generally to a chip extraction apparatus for use with a drill and more particularly to a chip extraction apparatus for use with a drill wherein the chip extraction apparatus contains means for extracting the chips from the drill flutes and the surface of the workpiece with an independent vacuum source and means for applying either liquid coolant/lubricant or pressurized air to the drill while the hole is being produced.
2. Description of the Prior Art
In modern drilling processes, it is desirable that chip swarf produced by the drilling operation be continuously removed from the drill flutes, the interior of the hole being produced, and the part surface. If the chip swarf is not adequately removed during the operation, the hole quality and drill life can become unacceptable and operator working conditions can be annoying and potentially unhealthy. Additionally, unremoved chip swarf can contribute to foreign object damage (FOD) to the product being manufactured should it become incorporated into the product; such incorporation may prevent the product from performing its function by obstructing orifices, preventing proper seating of parts during assembly, contaminating reservoirs, interfering with subsequent applications of protective coatings and adding undesired weight to the final product.
In current drilling procedures in which a drill's guide bushing is held in position by a drill plate located adjacent to the workpiece, the chip swarf is commonly either not extracted and left to accumulate in chip slots in the drill plate or is extracted by an external vacuum means which is entirely separate from the drilling equipment. The external vacuum means typically employs a hose and nozzle which is placed near the drilling location. However, in numerous drilling operations, large drill plates are utilized which severely limit the efficiency of the external vacuum means since it may be difficult or impossible to place the hose and nozzle near the drilling location. In the past multiple drill plates have been used to satisfy nozzle accessibility requirements, adding costs to manufacturing operations.
A method of extracting chip swarf in a drilling process is disclosed in U.S. Pat. No. 2,339,324 (hereinafter the '324 patent) by H. R. Fischer which issued on Dec. 9, 1941. The chip collecting attachment disclosed by the '324 patent has an external vacuum means for extracting chip swarf from the surface of the workpiece. However, the chip collecting attachment disclosed by the '324 patent has several deficiencies including the lack of an adequate supply of input air at the surface of the workpiece which severely limits the ability to extract large volumes of chips. The '324 patent contemplates input air being pulled between the drill bushing and the surface of the workpiece and into the flutes of the drill bit; however, this supply of air may be limited and insufficient for removal of large volumes of chips. An additional disadvantage is the use of a manual lever for providing a telescopic drill bushing which requires operator interaction and thus may decrease the efficiency of the drilling process. A further deficiency is the extraction of the chip swarf through a vacuum cavity which is partly restricted by the chuck and spindle of the drill. The chip swarf may jam or otherwise become entangled with the drill chuck and thus impair the drill's operation. The '324 patent also contemplates the use of a spring apparatus located on the external surface of the drill motor which could pose a safety hazard to the operator. The spring is a functional part of the telescopic drill bushing at the front end of drill unit. As the spring is compressed by the external lever an operator's hand could become injured by being caught between the spring coils as they compress.
An alternative method of extracting chip swarf in a drilling process is disclosed in U.S. Pat. No. 4,209,069 (hereinafter the '069 patent) by Bruce W. Smith which issued on June 24, 1980. The chip collecting drill disclosed by the '069 patent has a self-contained vacuum means for extracting chip swarf from within the drill's guide bushing and collecting the chips in a collection cup which is attached to the body of the drill. However, the drill disclosed in the '069 patent has several limitations and deficiencies. A spring positioned in the path of the chip flow will impede chip extraction by becoming entangled with chips during use and thereby hinder its utility. Additionally, a chip collector attached to the body of a drill will increase operator effort and the weight of the drill unit during use as chip swarf accumulates if it is designed to be large to prevent frequent cleansing. If the collector cup is small then frequent, time-consuming disattachment and cleansing, will be needed to keep unit operative. Furthermore, the use of a self-contained vacuum means can impose an additional load on the motor of the drill and thus decrease overall drill performance.
It would be desirable to develop a chip extraction means which is operable from an external vacuum source and which utilizes a direct and clear path for extracting the chip swarf. Additionally, it would be desirable for a chip extraction means to incorporate a means for applying coolant/lubricant or air at the drill point and into the entrance side of the hole before and during the drilling operation.